Journal of Natural Science, Biology and Medicine

ORIGINAL ARTICLE
Year
: 2020  |  Volume : 11  |  Issue : 1  |  Page : 7--11

Comparative evaluation of the effect of therapeutic ultrasound and transcutaneous electric nerve stimulation in temporalis and masseter myofascial pain


D. N. S. V Ramesh, Divya Nair, Pragati Kempwade, R Thriveni, Amit R Byatnal, Iram Rukhsar 
 Department of Oral Medicine and Radiology, AME'S Dental College and Hospital, Raichur, Karnataka, India

Correspondence Address:
Dr. Amit R Byatnal
Reader, Department of Oral Medicine and Radiology, AME'S Dental College and Hospital, Raichur, Karnataka
India

Abstract

Background: Myofascial pain is the one which originates from myofascial trigger points in skeletal muscle. The specific treatment should be aimed at finding the etiology and removing the root of cause, and when specific etiology is difficult to be determined, an oral physician should rely on treatment, which is less invasive and reversible, such as transcutaneous electrical nerve stimulation (TENS) and therapeutic US for pain and muscle dysfunction. Aim: The aim of this study was to determine and compare the therapeutic efficacy of ultrasound and TENS in the management of myofascial pain. Settings and Design: This study was a prospective and comparative study with randomized collection and division of samples with myofascial pain. Materials and Methods: Thirty patients with myofascial pain in the masseter and temporalis muscle were assigned into two different groups with 15 patients in each. Group 1 received TENS therapy and Group 2 received Th US. Both the groups were evaluated using the visual analog scale scale for pain. Statistical Analysis: The analysis was done using the Student's t-test (paired t-test and unpaired t-test) for intragroup and intergroup comparison. Results: The results showed a significant reduction in the mean pain score after treatment in Th US (2.07) as compared to TENS (3.20). There was no statistically significant difference between the two groups before treatment (P = 0.692); however, immediately after treatment, the difference was found to be significant (P = 0.003), and also significant in the 1 week follow up visit after treatment (P = 0.000). Intragroup comparison of pain index before and after treatment showed statistically significant differences (P = 0.000) within TENS and Th US group with the exception of comparison between posttreatment and the follow-up scores in Th US group (P = 0.301). Conclusion: It was concluded that the use of Th US when compared to TENS appeared to be better procedure for myofascial pain management.



How to cite this article:
Ramesh D, Nair D, Kempwade P, Thriveni R, Byatnal AR, Rukhsar I. Comparative evaluation of the effect of therapeutic ultrasound and transcutaneous electric nerve stimulation in temporalis and masseter myofascial pain.J Nat Sc Biol Med 2020;11:7-11


How to cite this URL:
Ramesh D, Nair D, Kempwade P, Thriveni R, Byatnal AR, Rukhsar I. Comparative evaluation of the effect of therapeutic ultrasound and transcutaneous electric nerve stimulation in temporalis and masseter myofascial pain. J Nat Sc Biol Med [serial online] 2020 [cited 2020 Jul 11 ];11:7-11
Available from: http://www.jnsbm.org/text.asp?2020/11/1/7/280122


Full Text



 Introduction



The World Health Organization has defined pain as “an unpleasant sensory or emotional experience associated with actual or potential tissue damage, or described in terms of such damage.” One such type of pain that is a major distressing condition and may significantly impact the quality of life, affecting the daily activities and functions, is musculoskeletal pain.[1]

Myofacial pain, a type of musculoskeletal pain, is a chronic pain affecting different facial muscles, usually evoked by the application of pressure on sensitive points in the muscles (trigger points).[2] It has been found that 30%–85% of the patients with musculoskeletal pain suffer from myofascial pain, usually in the age range of 27–50 years.[3] Such pain can be managed by multiple modalities including pharmacotherapy, physical therapy, and surgical techniques. Safer and advanced treatment modalities for modulating pain include transcutaneous electrical nerve stimulation (TENS) and therapeutic ultrasound (Th US).[2] The advantage of TENS therapy over others can be attributed to its noninvasiveness. Moreover, it has been found to be an efficient, safe, and relatively simple treatment option for chronic orofacial pain.[4]

One of the nonpharmacological techniques proposed for the treatment of myofascial pain is Th US. It converts electrical energy to sound waves to provide heat energy to the muscles.[5] Although multiple studies have yielded mixed results, the effectiveness of Th US for the relief of myofascial pain requires further testing.[6]

It is currently hypothesized that trigger points, the most common feature of myofascial pain, contain areas of sensitized low-threshold nociceptors (free nerve endings) with dysfunctional motor end plates. These motor end plates connect to a group of sensitized sensory neurons in charge of transmitting pain information from the spinal cord to the brain.[7] Temporalis muscle trigger points are responsible for evoking local and referred pain, especially in conditions such as chronic tension-type headache.[8] Moreover, it has often been hinted that myofascial pain may arise due to trigger points that are present in the masticatory muscles, commonly the masseter muscle.[9]

Thus, the aim of the present study was to evaluate and compare the efficacy of Th US and TENS in myofascial pain at the temporalis and masseter trigger points. By testing such alternatives, the patient can be enabled to depend less on analgesics and narcotics, eventually preventing drug dependence and various other side effects.

 Materials and Methods



The study was of a prospective type, conducted in AME's Dental College and Hospital, Raichur. At the start of the study, among the patients reporting to the hospital, the first thirty diagnosed with myofascial pain in the orofacial region either of master or temporalis origin, and meeting the inclusion criteria, were included as part of the study. Random assignment was carried out into the two groups – TENS therapy (Group A) and Th US (Group B), respectively [Figure 1], 15 each, using the lottery method. Informed written consent was obtained from the patient, and institutional ethical review board approval was obtained for conducting the study.{Figure 1}

The inclusion criteria were patients between 20 to 50 years with symptoms coinciding with myofascial pain as per Simons criteria.[10] Patients having the pain of odontogenic origin, postoperative pain, neuralgias, with temporary restorations, already treated with anti-inflammatory and analgesic drugs, and with the presence of any tumor or cancer around jaws or infections were excluded.

Pain intensity was recorded before and after treatment on the visual analog scale (VAS), with a score from 0 to 10. The extreme left-0 was considered as no pain, with an increase in intensity with the score, and the extreme right-10 was considered as unbearable pain.

Patient in Group A was treated with TENS electrodes placed at the trigger points elicited by tenderness on palpation with operating frequency of 50 Hz, pulse width of 0.5 ms, and the intensity as per the patient's tolerance, as it differs from person to person, for a total of 10 min continuously each day for 7 consecutive days [Figure 2]. Patients in Group 2 were treated with Th US over the trigger points for 8 min having intensity of 1.5 W/cm2 in continuous mode as a single session each day for 7 consecutive days [Figure 3]. At the end of 1 week of the treatment, all the patients were evaluated for pain using VAS and tenderness using digital pressure of 2 kgf. The pain values of Group A and Group B were compared before and after treatment.{Figure 2}{Figure 3}

Statistical analysis was carried out using IBM SPSS statistics 16.0 (Statistical Package for the Social Science IBM Corporation, Armonk, NY, USA). Demographic data were analyzed using descriptive statistics, and paired and unpaired t-test was done to compare pain values before and after treatment both between and within groups.

 Results



Among the 30 patients who were a part of the study, 83.3% (25) were females and 16.7% (5) were males. The gender distribution as per the individual groups was 86.7% (13) females and 13.3% (2) males in the TENS group and 80.0% (12) and 20% (3) females and males, respectively, in the Th US group. The mean age of the study population was 28.9 years ± 6.02 (standard deviation [SD]) with a range of 20–50 years. Among the Group A (TENS), the mean age was 28.4 years ± 6.92 (SD), and among the Group B (Th US), the mean age was 29.47 years ± 5.15 (SD).

The mean pain scores using the VAS in pretreatment TENS and Th US group were 5.53 ± 0.915 (SD) and 5.40 ± 0.910 (SD), respectively, and in posttreatment, they were 3.20 ± 0.941 (SD) and 2.07 ± 0.961 (SD), respectively. After a 1 week follow-up, the mean pain scores were 4.40 ± 0.941 and 2.33 ± 0.976.[Figure 4]. There was no statistically significant difference between the two groups before treatment (P = 0.692); however, it was significant after treatment (P = 0.003) and after 1 week posttreatment (P = 0.000).{Figure 4}

Intra group analysis of TENS group revealed statistically significant (P = 0.000) reduction in pain scores among pre and the post treatment as well as pretreatment and 1 week after the completion of treatment. The posttreatment and the follow-up scores also showed significant differences (P = 0.000). In the Th US group, intragroup analysis revealed a significant difference in the pre- and the posttreatment mean pain scores (P = 0.000), while the difference in posttreatment and the 1-week follow-up scores was found to be nonsignificant (P = 0.301).

 Discussion



The study compared the reduction in pain score obtained after 1 week of treatment, by TENS therapy versus Th US, in the temporalis and masseter muscle region, in patients suffering from myofascial pain.

The age distribution in our study is in line with other studies validating a common age of occurrence between the second and the fourth decades of life.[11] Studies by Dworkin et al.,[12] Isacsson et al.,[13] and Jensen et al.[14] similar to our study pursue a homogeneous female predisposition. Myofascial pain possesses multifactorial etiology comprising the inadequate dentitions, unsatisfactory occlusion, hyperfunction, temporomandibular jointas well as emotional disturbances.[15]

Management of patients with chronic myofascial pain at the orofacial region often presents a challenge to the clinician because of its complex and variable nature. Hence, our study objective was to modify the chronic myofascial pain using less invasive modalities as well as to find the most appropriate modality for the same.

The use of TENS in chronic pain was first introduced Shealy in 1967.[16] TENS is a renowned treatment modality that utilizes a controlled, low-voltage electric current to stimulate the nerve fibers to alleviate pain. It uses electrical impulses of variable frequency and wavelength transcutaneously through electrodes placed over the skin leading to the production of local analgesia. It acts as a valid alternative to surgery when pharmacological therapy fails. The mechanism of action of TENS is explained by several interrelated theories. A few of these theories include the gate control theory, endogenous pain control theory, etc.[2],[17]

Our study showed a significant improvement in the mean pain values when treated with TENS. Similar results were obtained by Rodrigues et al.,[18] Kato et al.,[19] and Moger et al.,[20] who proved a significant reduction in pain intensity and discomfort using single TENS application in myofascial pain. Rajpurohit et al.[21] substantiated the pain-relieving capability of TENS on masticatory muscle pain in bruxism patients.

Th US is a noninvasive therapeutic approach which includes vibrations above 16,000 vibrations/s or 16 Hz (range audible to the human ear) and a frequency ranging from 1.0 to 3.0 MHz focused to accelerate healing, decrease joint stiffness, alleviate pain, increase the extendibility of collagen fibers, and reduce the muscle spasm.[22] In myofascial pain, Th US acts by converting electrical energy to sound waves and transmits heat energy to muscles. Ultrasonic massage is a potential mechanical stimulus and an effective inhibiting capability on the pain gate process leading to reduced discomfort, greater release of opiates, and profound pain suppression.[23]

Theories on the mechanism of action of US therapy in myofascial pain control include increased blood flow leading to the washout of pain-causing mediators from the environment, nerve conduction changes or cell membrane permeability changes leading to reduced inflammation, increased capillary density in muscle tissue, energy consumption improvement in the cell, increased angiogenesis in ischemic tissue and acceleration of the healing of tissue, and improved persistent muscle spasm.[24]

Similar to our study, Esposito et al.[25] also concluded that ultrasound is most successful in alleviating muscle pain, while Esenyel et al.[26] proved its effectiveness similar to the trigger point injections. Majlesi and Unalan[27] observed high-power ultrasound more effective than conventional ultrasound in chronic pain of the trapezius muscle. Rai et al.[28] showed the ultrasonographic features of masseter muscle pre- and postultrasonic massage using diagnostic ultrasound and even proved better results in modifying pain compared to TENS. Our results reflected pain reduction in the masseter and temporalis trigger points on the application of both TENS therapy and Th US. The literature elicits the lack of researches comparing the efficacy of TENS therapy and Th US in modifying myofascial pain.

 Conclusion



TENS as well as Th US offers clinicians an excellent entry point to modify patient's acute and chronic pain problems. As proven in our study, ultrasound is a step higher than TENS in pain alleviation and hence can be relied by dentists for soothing and targeting a pain-free ambiance for the patients.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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